JPH06254470A - Drying device - Google Patents

Abstract

PURPOSE:To enhance drying effect, in a drying device for applied paint, by arranging a plurality of lamp blocks consisting of infrared lamps in a hot air drying oven in the feed direction of an object to be coated at a prescribed interval so that the sum total of irradiation energies from the respective lamp blocks becomes a prescribed range. CONSTITUTION:Lamp blocks 5, 6 each consisting of infrared lamps or a plurality of near infrared lamps with lambda max of 1.2-1.5mum are provided in a hot air drying oven 2 in the feed direction of a conveyor 3 for feeding an object to be coated. The lamp blocks 5, 6 may be two or more and can be also provided in an up-and-down or left-and-right direction. The lamp blocks 5, 6 are arranged at a prescribed interval so that the sum total of irradiation energies applied to the object to be coated passing between the lamp blocks 5, 6 becomes the range of 70-100%, pref., the range centering around 100%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying device, and more specifically, it applies a coating material, a printing ink, an adhesive agent or the like to an object to be coated, and applies the same in a hot air drying oven provided with a plurality of infrared lamps. The present invention relates to a drying device that irradiates an object with infrared rays to heat and dry it.

[0002]

2. Description of the Related Art Generally, in a hot-air drying oven, melamine / alkyd resin paints are heated at 120 ° C. for 20 minutes and thermosetting acrylic resin paints are heated at 140 to 150 ° C. for 20 minutes. Further, recently, a method of providing an irradiation device such as a far-infrared ray, a mid-infrared ray, and a near-infrared ray lamp in a hot air drying furnace to increase the heating and drying effect is being widely adopted.

In these irradiation devices such as far-infrared rays, mid-infrared rays, and near-infrared rays lamps, a plurality of lamp blocks each having a plurality of infrared lamps as one block are provided along the traveling direction of the article to be coated, The article to be coated is made to advance to the front surface side with an appropriate interval.

Irradiation devices such as far-infrared rays, mid-infrared rays, and near-infrared lamps rapidly raise the temperature inside the drying oven and, with respect to organic polymers found in paints, printing inks, adhesives, etc., Its main purpose is to absorb wavelength energy in the infrared region and accelerate drying by molecular motion.

[0005]

However, the method of installing the irradiation device such as the far-infrared ray, the mid-infrared ray, and the near-infrared ray lamp in the drying furnace has not been sufficiently studied. Irradiation devices such as infrared lamps according to the prior art have a drawback that if the lamp blocks are installed in close proximity to each other, drying will be accelerated, but defects such as foaming and discoloration due to rapid heating are likely to occur.

On the contrary, when the installation interval is increased, defects such as foaming and discoloration are eliminated, but the drying effect is reduced, the drying device is enlarged, the installation space is increased, and the economy is poor. . In addition, it was difficult to automatically control the uniformity of the infrared irradiation amount due to changes in the conveyor speed.

[0007]

The present invention has been made in view of the above-mentioned problems, and the drying device according to claim 1 is
In a drying device for applying a coating material, a printing ink, an adhesive agent or the like to an article to be coated, and irradiating the article to be coated with infrared rays in a hot-air drying oven provided with a plurality of infrared lamps to heat and dry it,
In the hot air drying oven, a plurality of lamp blocks each including a plurality of infrared lamps as one block are provided along the traveling direction of the article to be coated, and when the article to be coated passes between the lamp blocks, each lamp block is provided. It is characterized in that the lamp blocks are arranged at intervals such that the total irradiation energy applied from the blocks to the object to be coated is in a range centered on 100%.

Further, in the drying apparatus according to the second aspect of the present invention, the object to be coated is coated with the heat-curable coating material, and the object to be coated is irradiated with near-infrared rays in a hot-air drying oven provided with a plurality of infrared lamps. In the drying apparatus for heating and drying, the hot air drying furnace is provided with at least a plurality of lamp blocks each having a plurality of near-infrared lamps of λMax 1.2 to 1.5 μm as one block along the traveling direction of the object to be coated. The total irradiation energy applied to the object to be coated from each lamp block when the object to be coated passes between the lamp blocks is 70 to 1
It is characterized in that the lamp blocks are arranged at intervals such that the range is centered at 00%.

[0009]

According to the drying device of the first aspect of the present invention,
In the hot-air drying oven, a plurality of lamp blocks each having a plurality of infrared lamps as one block are provided along the traveling direction of the object to be coated, and the object to be coated with paint, printing ink, adhesive, etc. is the lamp block. The total irradiation energy given to the coated object from each lamp block is 1 when passing through the space.
Since the lamp blocks are arranged at intervals so that the range is centered at 00%, that is, when the lamp block passes through the front surface of each lamp block, the irradiation energy given from the lamp block is 100%. %, 50% of the irradiation energy is given from one lamp block and 50% of the irradiation energy is given from the other lamp block at the central position between the lamp blocks, and these irradiation energies are overlapped. Energy is 100% in total, and when the article to be coated progresses between a plurality of lamp blocks each including a plurality of infrared lamps as one block, a constant irradiation energy is always received, and the drying efficiency is improved. You can

According to the coating material drying apparatus of the second aspect of the present invention, the hot air drying furnace has a plurality of lamp blocks each having a plurality of near-infrared lamps of λMax 1.2 to 1.5 μm. Is provided at least in the advancing direction of the article to be coated, and the total irradiation energy applied to the article to be coated from each lamp block when the article to be coated passes between the lamp blocks is in a range around 70% to 100% Since the lamp blocks are arranged so as to be spaced apart from each other, assuming that the irradiation energy given from the lamp blocks to the object to be coated when passing through the front surface of each lamp block is 100%, the distance between the lamp blocks is increased. At the central position, one lamp block gives 35 to 50% irradiation energy, and the other lamp block gives 35 to 50% irradiation energy. Since these irradiation energy overlap next total from 70 to 100% of the radiation energy,
When the object to be coated advances between a plurality of lamp blocks each including a plurality of near-infrared lamps as one block, insufficient drying does not occur and a constant irradiation energy is received, so that the drying efficiency can be improved. it can.

[0011]

The following is a more detailed description of the paint drying apparatus according to the present invention. The heat-curable coating used in the present invention may be any as long as it can be cured by ordinary heating, for example, melamine-alkyd resin coating, acrylic-melamine resin coating, polyurethane resin coating, epoxy resin coating and Examples include various powder resin paints. These paints are applied to the target article by a known method to form a coating film. It should be noted that what is dried and cured by the drying device of the present invention is not limited to the paint, and printing ink,
It may be an adhesive or the like.

FIG. 1 shows an embodiment of a drying device 1 of the present invention. The drying device 1 is a hot air drying oven 2 and a conveyer 3 for conveying an object to be coated to the hot air drying oven 2. The hot air drying furnace 2 has a plurality of infrared lamps for irradiating the coated object with infrared rays. A plurality of lamp blocks 5 and 6 having a plurality of infrared lamps as one block are provided along the traveling direction of the object to be coated in the hot air drying furnace 2. The lamp blocks 5 and 6 are shown as a pair of left and right, but they may be provided in the vertical and horizontal directions, or may be two or more blocks.

In the hot air drying oven 2, the total irradiation energy applied to the object to be coated from each of the lamp blocks 5 and 6 when the object to be coated passes between the lamp blocks 5 and 6 is around 70 to 100%. Range, preferably 100%
The lamp blocks 5 and 6 are arranged at intervals such that the range is centered at.

As the infrared lamp installed in the hot-air drying furnace 2, it has been found that the near-infrared lamp already studied by the present inventors is most effective. The distance between the lamp blocks 5 and 6 is indicated by Xmm in FIG. Also conveyor 3
The speed is 1-2 m / min. The distance from the near-infrared lamp blocks 5, 6 to the conveyor 3 through which the article to be coated depends on the material of the article to be coated is 200 to 400 mm, preferably 3
It is 00 mm.

The present inventors conducted an experimental study on the proper positions of the lamp blocks 5 and 6 installed in the hot air drying furnace 2. The experiment is a steel plate of 300 mm to 300 mm (thickness 1.2 mm)
Was spray-coated (cured coating thickness: 30 to 35 μm) with a usual melamine resin baking (thermosetting) coating. Standard curing and drying conditions for the melamine resin baking coating are 120 ° C. and 20 minutes.

Further, the infrared lamp installed in the hot air drying furnace 2 is a near infrared lamp (λMax 1.2 to 1.5 μm,
Since it has been found that 1 kw × 3 lines is one block), the near infrared lamp blocks 5 and 6 were used for verification. Conveyor speed is 1m / mi
n, so the cure drying time is 3 minutes.

The melamine resin coating material used in this experiment has a hardness H (pencil hardness) in the usual curing and drying. The distance from the near-infrared lamp blocks 5 and 6 to the conveyor 3 through which the article to be coated passes was set to 300 mm.

The results are shown in Table 1.

Table 1

In Table 1, two 3kw near-infrared lamp blocks 5 and 6 in the hot air drying furnace 2 are installed, and the installation interval Xmm.
And the state of the coating film, and the drying time is 3 minutes in each case.

Further, the lamp block interval X = 1000 mm
Then, in order to obtain the hardness H in 3 minutes like the lamp block interval X = 400, one lamp block had to be added in the middle.

From Table 1 showing the results of these experiments, it can be seen that it is effective that the distance Xmm between the near-infrared lamp blocks is around 400 mm. Furthermore, when the conveyor speed is 1.5 times, three lamp blocks are installed, and when it is twice, four lamp blocks are installed, and the drying furnace is extended so that the curing and drying time is 3 minutes. The same results as in Table 1 were obtained. That is, when the lamp block interval was shortened or lengthened, poor appearance such as foaming and insufficient curing and drying occurred.

The object to be coated is the lamp block 5, which is the central position between the lamp blocks 5 and 6 when the irradiation energy density per unit area is 100% when the distance from the front surface of the near infrared lamp of the lamp block 5 is 300 mm. The position of 175 to 200 mm from the lamp block 6 is a position which receives 50% of the irradiation energy of the lamp block 5.

When the object to be coated reaches this central position, this time the near infrared lamp of the lamp block 6 in the traveling direction 5
Since it receives irradiation energy of 0%, it receives the same irradiation energy as when it is in front of the near infrared lamps of the lamp blocks 5 and 6. When arranged at this interval, the object to be coated always receives almost the same energy.

The appropriate irradiation energy density to be applied to the object to be coated is determined from experiments, and the near-infrared lamp should be arranged so that the irradiation energy is always applied to the object to be coated uniformly. If the intervals are set so that the irradiation energy becomes high, it causes appearance defects such as foaming and discoloration,
This is because the drying and curing will be reduced if the installation is performed with a large interval so that the energy becomes small.

In the present invention, when the object to be coated is cured by irradiating with near-infrared rays, the near-infrared rays may be radiated in a heating furnace whose inner wall surface is made of a material of far-infrared ray radiating material. .

[0027]

The structure of one embodiment of the drying apparatus according to the present invention has been described above. According to this structure, the hot air drying furnace has a plurality of lamp blocks each including a plurality of infrared lamps. Is provided along the traveling direction of the object to be coated, and the irradiation energy applied to the object to be coated from each lamp block when the object to be coated with paint, printing ink, adhesive, etc. passes between the lamp blocks. Since the lamp blocks are arranged at intervals so that the total of the lamp blocks is centered around 100%, irradiation energy of 50% is given from one lamp block at the central position between the lamp blocks. , 50% of the irradiation energy is given from the other lamp block, and these irradiation energies overlap, so the total of the irradiation energy becomes 100%, and multiple infrared lamps When the article to be coated progresses between a plurality of lamp blocks that form one block, it receives constant irradiation energy at all times, so that the drying efficiency can be improved and the coating film can be quickly cured in a short time. It is possible to prevent coating film defects such as pinholes and discoloration due to foaming, and it is possible to obtain a drying device having extremely excellent economical efficiency.

Further, the lamps are arranged at intervals such that the total irradiation energy applied to the object to be coated from each lamp block when the object to be coated passes between the lamp blocks is in a range centered on 70 to 100%. When the blocks are arranged, irradiation energy of 35 to 50% is applied from one lamp block and irradiation energy of 35 to 50% is applied from the other lamp block at the central position between the lamp blocks. Since these irradiation energies overlap, the total irradiation energy becomes 70 to 100%,
When the object to be coated advances between a plurality of lamp blocks each including a plurality of near-infrared lamps as one block, insufficient drying does not occur and a constant irradiation energy is received, so that the drying efficiency can be improved. In addition, it is possible to prevent coating film defects such as pinholes and discoloration due to foaming, and it is possible to obtain a drying device having extremely excellent economical efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory plan view of a hot air drying furnace showing an embodiment of a drying device according to the present invention.

[Explanation of symbols]

 1 Drying device 2 Hot air drying furnace 3 Conveyor 5 Lamp block 6 Lamp block

[Table 1]

Claims (2)

[Claims] 1. A drying apparatus for applying a coating material, a printing ink, an adhesive agent, etc. to an object to be coated, and irradiating the object to be infrared ray with a hot air drying oven equipped with a plurality of infrared lamps to heat and dry the object. The hot-air drying oven is provided with a plurality of lamp blocks each including a plurality of infrared lamps as one block, and each lamp block is provided when the object passes between the lamp blocks. A drying device, in which lamp blocks are arranged at intervals such that the total irradiation energy applied to the article to be coated is from 100%. 2. A hot-air drying apparatus for applying a heat-curable coating material to an object to be coated, and irradiating the object to be coated with near-infrared rays for heating and drying in a hot-air drying furnace equipped with a plurality of infrared lamps. In the furnace, a plurality of lamp blocks each having a plurality of near-infrared lamps of λ Max 1.2 to 1.5 μm as one block are provided along the traveling direction of the object to be coated, and the object to be coated is between the lamp blocks. The lamp blocks are arranged at intervals so that the total irradiation energy applied to the object to be coated from each lamp block when passing through is around 70 to 100%. Drying device.